some peoples brains just operate faster, like have a faster clockspeed in the same way CPUs do. i feel like people who can read extremely fast also correlate strongly to people who can listen to audio very fast. my partner is an unbelievably fast reader, like the fastest i've ever seen, but she also has a phd in maths and is generally brilliant, i have no idea where im going with this. some peoples brains are just wired for high amounts of data bandwidth. but also practice, and it also depends on the original speed of the speaker/content.